If it happened to me, and it occurred to me to show them the receipt, I'd expect them to snatch it from my hand, tear it into pieces and throw it away with a fed-up gesture, and then to keep going back to the shop with the item I allegedly stole, without losing their angry countenance or the certainty that they're doing the right thing.
Oh, and I'd also expect them to enforce the ban fiercely if I dared to go back to the shop, too, calling the police if I insisted---with no proof anymore at this point---that they're the ones who robbed me. I guess I'd end up processed for slandering them, in addition to beaten up by them when I pestered them too much with my useless complaint.
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The red lake has been forgotten. A dust devil stuns you long enough to shroud forever those last shards of wisdom. The breeze rocking this forlorn wasteland whispers in your ears, “Não resta mais que uma sombra”.